if it's outside to the TM box (outside), it's TM matter.
u complain, they must fix for free, this is t heir infra.

however, from the box to your modem, u bear the cost.
if u ask TM people com & do, it's expensive.
u can get 3rd party in which u hav 2 options.
1) get the fiber cable & replace the whole cable, meaning u hav to relay the internal fiber wiring.
2) cut & patch the part that is broken. degration is expected, but this 1 depends on quality of work.

TM gonna charge u a bomb.
u can get the fiber cable outside also. although not common, but can find.